Lapper for carbide tipped tools



june 26, 3956 K. LINDMARK LAPPER FOR CARBIDE TIPPED TOOLS 3 Sheets-Sheet1 Filed Feb. 6, 1953 12% KezvZ L. L z'z zdzzzaz" 31109 1956 K. L.LINDMARK LAPPER FOR CARBIDE TIPPED TOOLS 3 Sheets-Sheet 3 Filed Feb. 6,1953 IIHI I HUIHHTIHI IIII km 9w United States Fatent LAPPER FGR CARBIDETIPPED TOOLS Karl L. Lindmark, Loves Park, 111., assignor, by mesneassignments, to Feniind Engineering Co., Loves Park, 111., a corporationof Illinois Application February 6, 1953, Serial No. 335,459

7 Claims. (Cl. 51-135) This application relates to improvements upon thedis closure of my copending application, Serial No. 318,360, filedNovember 3, 1952, which resulted in Patent No. 2,663,978, issuedDecember 29, 1953.

This invention relates to a machine for lapping carbide tipped tools,said machine incorporating a wheel of medium large diameter having awide fiat rim with a smooth true periphery which serves as a precisionsupporting pulley for an endless belt of abrasive material that is keptevenly tensioned and running true while driven by means of a smallermotor driven pulley, the wheel and belt thereby cooperating to providean endless unyielding precision lapping surface to a lap or polish onthe arcuate contour of the Wheel to obtain a micro-finish on the tip ofa cemented carbide tool bit accurately to a predetermined angledetermined 'by the setting of a horizontal tool support at apredetermined elevation with respect to the working face of the wheel.

The principal object of my invention is to facilitate the operation ofthis machine by the provision of a direct reading height gauge for usein combination with the height adjustment in connection with the slidethat serves as an adjustable tool support, this height adjustment, inaccordance with the present invention, being operable in either of twoways, depending upon the closeness of accuracy desired and upon how muchor how little time the operator is prepared to spend in making saidadjustment. The more accurate method, which takes more time, involvessetting the micrometer adjustment according to a table of measurementsshowing the height adjustment for a pillar that carries the toolsupporting slide, there being in this table of measurements one for eachangle of lap calculated to three decimal places according to the toolheight measured from the slide. The other method, which is accurateenough for most purposes and means a big saving in time for theoperator, involves setting the micrometer adjustment according to thenovel direct reading height gauge, the tool bit being placed on theslide and extended therefrom into close proximity to the vertical gaugepost on the flat face of which are graduations in vertically spacedrelation, each graduation representing one specific angle in a rangefrom 1 to so that the operator need only raise or lower the slide to thepoint where the tip of the tool bit registers with the appropriategraduation line. In the event a setting of closer accuracy is desired,the operator can by reference to the table of measurements ascertain theexact reading that should appear on the micrometer for the given toolheight and the angle desired and then make a fine adjustment one way orthe other to get that exact reading. The direct reading gauge ispreferably provided on the outer end of an arm pivoted on a verticalaxis on the frame to swing in a horizontal plane from a retractedposition parallel to and spaced from the front of the tool supportingslide to an operative position at right angles to said slide Where thegauge is disposed in close enough proximity to the frQnt of. the slideto enice able accurate setting of the micrometer adjustment using saidgauge in the manner described.

The invention is illustrated in the accompanying drawings, in Which-Fig. l is a top view and Fig. 2 is a side view of a lapping machineincorporating the direct reading height gauge made in accordance with myinvention;

Fig. 3 is a geometrical diagram showing how the dif ferent angles ofmicro-finishes are obtainable by different heights of adjustments forthe tool support pillar in relation to the wheel;

Fig. 4 is a table of height adjustments for the tool support pillarcalculated for each of a series of angles in relation to tool heightsmeasured from the tool support slide;

Fig. 5 is an enlargement of a portion of Fig. 2 to better illustrate thedirect reading gauge, which appears in side elevation, and

Fig. 6 is a front view of Fig. 5.

The same reference numerals are applied to corresponding parts in thesesix views.

Referring to the drawings, the machine illustrated in Figs. 1 and 2 islike that disclosed and claimed in the copending application and thereference numeral 10 designates a table forming a part of the frame ofthe machine supported on legs 11 at a convenient elevation with respectto the floor. A base plate 12 for support of the electric motor 13 anddrive pulley 14 fixed to the armature shaft 15 of the motor is supportedon the flat top surface 16 of the table 10 for oscillation relative to apivot pin 17 fixed to the table 10 and received in a hole 13 in theplate, whereby to permit oscillation of the pulley 14 about a verticalaxis ab that extends through the axis of the armature shaft 15 at themiddle of the pulley 14. This is to enable making the abrasive belt 19that runs on the pulley 14 and the wheel 20 as a driven pulley trackproperly and run absolutely true, that is, without any perceptiblewabble. A screw-thread adjustment is provided which enables fineadjustment of plate 12 in either direction, the adjusting meansincluding a rod 21 supported for rotation and against endwise movementin a bearing 22 fixed with respect to the top of the table 10. Ahandwheel 23 is attached to the projecting end of the rod 21 adjacentthe bearing 22, and the other end of the rod is threaded, as indicatedat 24, and entered in a nut 25 slidable in a bearing 26 fixed to thetable 10. The nut 25 carries a pin 27 slidably pivotally engaged in aslot 28 provided in a lug 29 projecting from the plate 12. Thus, one mayjog the plate 12 angularly a little one way or the other about the axisab so as to make the belt 19 run without any perceptible wabble, asrequired for lapping a true finish.

The motor 13 is also swingable on a horizontal axis with respect toplate 12, as indicated by the pivotal mounting 38, with a view tomaintaining the abrasive belt 19 under uniform tension by reason of thetendency of the motor 13 to gravitate about the axis 30 away from wheel26. However, there is provided under one end of the base 31 of the motor13 a nearly semicircular cam 32 that is provided as a machined end of ashaft mounted in a bearing 33 provided on one end of plate 12. The camshaft is adapted to be turned by means of a hand lever 34 through 186 tolift the base 31 of the motor 13 to the extent indicated by the dottedinclined line cd shown in Fig. 2 whereby to free the belt 19 so that itmay be easily removed and replaced when worn beyond further use. In likemanner, if the belt requires jogging one Way or the other to a centralposition on pulley 14 and wheel 20, that can be done readily byreleasing the tension in the manner just described.

The wheel 20 and abrasive belt 19 cooperate to pro- 3 vide an endlessunyielding precision lapping surface on which to lap or polish on thearcuate contour of the wheel to obtain a micro-finish on the tip of awelded carbide tool bit like that indicated at 35 in Fig. 2. The bit 35is mounted on a tool support or slide 36 and sometimes it is positionedat a desired angle by abutment alongside a protractor slidable back andforth in a groove 36 extending crosswise of the slide parallel to theWorking face of the abrasive belt'19. The tool support 36 is adjustablein and out toward and away from the belt 19 and wheel on a table 37carried on a vertically adjustable pillar 38, the in and out adjustmentbeing obtained by means of a screw 39 rotatable in a bearing 49 on thesupport 36 and threading in a hole in the table 37. The angle of thesurface 41 lapped so accurately on the tip of'the tool bit is determinedby the elevation of the pillar 38 and hence the support 36 with respectto the working face of the wheel, it being manifest from an inspectionof Fig. 2, in which the top of the support 36 on which the tool bit 35rests is shown disposed in the plane of the horizontal line ef passedthrough the center of the wheel 20, that the higher the elevation of thetool support 36 the greater the angle lapped at 41, measuring from avertical. Although the surface 41 lapped on this machine is on a radiusdetermined by the radius of the wheel 20, that radius is large enough inrelation to the thickness of the tool bit 35 for the surface 41 to beconsidered substantially flat. Merely by way of example but not in anysense as indicating a limitation on this invention, I may state that thewheel 20 in the machine heren in shown is of a 7-inch radius and I havefound that this gives good results. The important features, as I atpresent see them, are:

(l) the lineal speed of the abrasive belt 19;

(2) the type of abrasive belt 19;

(3) the type of cooperating wheel 20, and

(4) the relationship of the tool support 36 to the contour of the wheel20 so as to obtain the proper angularity of the surface 41 on thecarbide tipped tool bit 35.

The abrasive belt 19 and wheel 29 combination replace the so-calleddiamond wheels, which are made of diamond chips or dust. This novelcombination does a much better job using far less expensive abrasivebelts 19, like the silicon carbide belts that were used heretofore onlyfor polishing glass, ceramics, and non-ferrous materials. There again,the mention of silicon carbide should not be taken as in any sense alimitation on the invention, inasmuch as other abrasive materials coulddoubtlessly be used to equal, if not better, advantage. The belt 19 ispreferably, though. not necessarily, one constructed with a clothbacking and made quite thin and pliable and without any appreciablevariation in thickness throughout the length thereof, that is, withoutany overlapping of ends. Inasmuch as the machine must be constructed sothat the periphery of thewheel will be true and have a hard surface,because there must be no cushioning action, the wheel 29 is preferablyof cast iron or meehanite having a wide flat rim 42 with a smooth trueperiphery 43. A sheet metal dust and safety guard, only a portion ofwhich is indicated at 44 in Fig. 2, is preferably provided suitablyattached to the'table 10 and enclosing the major portion of the-wheel 20and pulley 14 and the abrasive belt 19 operating thereon, leavingexposed for performance of the lapping operation a portion of the frontof the wheel 20 above and below'the tool support 36. Dust dischargeddownwardly from the front of the wheel is conducted through the passage45 into a pan 46 that is removably suspended on the front of themachine, as indicated at 47. Any suitable precision'bearing support ofthe kind shown may be provided for the wheel 20, it being, of course,very important that the periphery 43 of rim .42 be truly concentric tothe axis of rotation, because its trueness is the basiso'f themicro-finishes lapped on thetoolbits. "Q

The pillar 38 supporting the table 37 is slidable in a vertical guidebearing 48 provided on the front end of the table 10 and has a keyway 49in which the inner end of a screw 50 is slidably received to hold thepillar against turning, and, when the screw is tightened, lock thepillar in an adjusted position. An axial hole 51 provided in the lowerend of the pillar is threaded and receives a pillar adjusting screw 52that is swivelled in a bearing 53 for rotation with a hand wheel 54.This hand wheel-is graduated on the periphery from zero to 125 and thethreads on the screw 52 are so related to these graduations that onecomplete revolution of the wheel means a vertical adjustment of .125,namely, /8 inch. The pillar 38 has graduations thereon in eighths of aninch, so that the operator can tell partly from the reading on thepillar 33 and partly by reference to the reading on the wheel.

54, what the machine is set for, down to a thousandth of an inch. Thewheel 54, of course, turns with reference to an index mark M on thefront of the table 10, where the reading on the wheel 54 is taken. Thescrew 50 is loosened whenever the height adjustment of the tool support36 is to be changed, and this screw is tightened again after such anadjustment.

Referring to Figs. 3 and 4, which illustrate one method of operation,using a table of measurements to determine the micrometer adjustment forthe elevation of the slide 36, the are 43 represents a portion of theperiphery of the rim 42 of wheel 20 with the abrasive belt thereon, asindicated at 19. The dimension 55 is what appears on pillar 38 when thetool support is at zero elevationnamely, at line ef, Fig. 2. Thedimensions indicated at 56 are elevations above the horizontal plane ofthe line ef for a series of angles 515. In other words, a line drawntangent to the are 43 at any one of these scaled points makes an angle Ato the vertical equal to that indicated adjacent the dimension, theangle A illustrated in Fig. 3 being 15. Now, referring to the table 57shown in Fig. 4, it will be seen that for each angle from 5 to 15 thereis a series of dimensions 58 and that these are in columns under theheadings A", /8, etc., to 2", which refer to tool height or thickness.The operator, as directed in the instructions 59, first determines thetool height; then he sets the pillar 38 to the height shown in the tableunder that tool height. Thus, if it is say a A" tool bit the dimensionindicated for at 5 angle is 1.750. That checks with Fig. 3 becausel.390-}-.6l0=2.000, and 2.000.250=1,750. .The slide 36 is accordinglyset very accurately to lap the specified ang e.

I Referring next to Figs. 5 and 6, which illustrate another method ofoperation, using the direct reading gauge 60 provided in accordance withthe present invention in determining the elevation of the slide 36, thetool bit 35 in accordance with this method is placed on the slide andextending therefrom, as indicated in dotted lines in Figs. 2 and 5, intoclose proximity to the flat front face 61 of the gauge postwherevertically spaced graduations 62 are provided, as clearly appearsin Fig. 6, to indicate the various levels for the various angles oflapping. These graduation lines are .125" apart and the numerals from Oto 15 indicate the angles measured from a vertical. The operator,therefore, need only raise or lower the slide 36 to the point where thetip of the tool bit 35 registers with the graduation linefor the desiredangle. Such a setting is accurate at leastto two decimal places and if asetting of closer accuracy to the third decimal place is desired, theoperator can by referring to the table 57 estimate the actual micrometerreading for the given tool height and the angle desired and then makewhatever slight correction in the setting of the wheel 54 may benecessary to get that exact reading. The gauge post 60 is providedpreferably on the outer end of an arm 63 that is pivoted on a verticalaxis on a pin 64 that has a press fit in a hole 65 provided in aprojection 66 on the front of the wheel support 67. An accuratelymachined washer 68 spaces the arm 63 from the top face of the projection66' so that the arm 63 may be swung easily from a retracted positionparallel to and spaced from the front of the tool supporting slide 36 toan operative position substantially at right angles to said slide, wherethe gauge post 6%, as clearly appears in Figs. 2 and 5, is disposed inclose enough proximity to the front of the slide 36 to enable accuratesetting of the micrometer adjustment, using the gauge 63 in the mannerdescribed. This method of operation is accurate enough for most purposesand means a big saving in time for the operator. Many of these lappingmachines will not be equipped with a table 57 for that reason, accuracyto a second decimal place being sufiicient for most work.

In conclusion, attention is called in Figs. 1 and 2 to an eccentric 69on the end of a stub shaft 70 mounted in a bearing 71 provided in thesame projection 66 that carries the pin 64. A lever 72 is attached tothe shaft 70 and is shown in Fig. 2 in raised operative position holdingeccentric 69 frictionally engaged with the inner periphery of the rim 42to stop rotation of the wheel 20. The lever 72 is otherwise swungdownwardly into abutment with the table holding eccentric 69 inretracted relationship to the rim of the wheel 20. Quick stoppage of thewheel saves time for the operator when a belt 19 is worn and has to bereplaced.

it is believed the foregoing description conveys a good understanding ofthe objects and advantages of my invention. The appended claims havebeen drawn to cover all legitimate modifications and adaptations.

I claim:

1. In combination, an endless abrasive belt of suitable width, asuitably rotatably supported wheel of appreciable radius having a rimwith a wide fiat smooth unyielding periphery on which said belt operatesunder tension, means for driving said belt and wheel, a work supporthaving a surface in a plane parallel to a radius of said wheel on whicha tool bit the tip of which is to be lapped by contact with saidabrasive belt is adapted to be carried, a pillar on top of which saidsupport is carried for adjustment in a direction parallel to a tangentto said wheel, a guide for said pillar, means for adjusting said pillarin said guide, and an elongated gauge member disposed adjacent said worksupport parallel to said pillar on the face of which toward the worksupport are provided transverse graduations spaced longitudinally ofsaid gauge member, said graduations indicating directly the differentlevels for supporting a tool bit for lapping dilterent angles on thetool bit tip, whereby said work support with a tool bit resting thereonwith the tip disposed adjacent said gauge member is adapted to beadjusted to a predetermined position for a predetermined angle oflapping by adjusting it with the tool bit movable in close proximityrelative to the gauge member.

2. In combination, an endless abrasive belt of suitable width, asuitably rotatably supported wheel of appreciable radius having a rimwith a wide fiat smooth unyielding periphery on which said belt operatesunder tension, means for driving said belt and wheel, a work supporthaving a surface in a plane parallel to a radius of said wheel on whicha tool bit the tip of which is to be lapped by contact with saidabrasive belt is adapted to be carried, a pillar on top of which saidsupport is carried for adjustment in a direction parallel to a tangentto said wheel, a guide for said pillar, means for adjusting said pillarin said guide, said pillar adjusting means including means giving amicrometer reading for each adjustment, said combination including atable of figures representing difierent micrometer measurements in whichthere is correlated with the angle of lapping desired the predeterminedmicrometer measurement for pillar adjustment for each of a series oftool bits of diflerent thicknesses, and an elongated gauge memberdisposed adjacent said work support parallel to said pillar on the faceof which toward the work support are provided transverse graduationsspaced longitudinally of said gauge member for indicating any givenpillar adjustment independently of the means indicating the micrometeradjustment of the pillar, said graduations indicating directly thedifferent levels for supporting a tool bit for lapping difierent angleson the tool bit tip, whereby said work support with a tool bit restingthereon with the tip disposed adjacent said gauge member is adapted tobe adjusted with the micrometer adjustment to a predetermined positionfor a predetermined angle of lapping by adjusting it without referenceto the micrometer readings and with the tool bit movable in closeproximity relative to the gauge member and the pillar adjustment is thenadapted to be corrected by only a slight amount of operation of themicrometer adjustment to secure a micrometer reading given in the tableof figures so as to get the pillar adjusted more accurately to theprescribed micrometer measurement for the given tool and the angle oflapping desired.

3. in combination, an endless abrasive belt of suitable width, asuitably rotatably supported wheel of appreciable radius having a rimwith a wide flat smooth unyielding periphery on which said belt operatesunder tension, means for driving said belt and wheel, a work supporthaving a surface in a plane parallel to a radius of said wheel on whicha tool bit the tip of which is to be lapped by contact with saidabrasive belt is adapted to be carried, a pillar on top of which saidsupport is carried for adjustment in a direction parallel to a tangentto said wheel, a guide for said pillar, means for adjusting said pillarin said guide, said work support including a slide on which the work iscarried adjustable in a direction at right angles to the pillar andparallel to the radius of said wheel toward and away from the peripheryof the wheel, and an elongated gauge member disposed adjacent said worksupport parallel to said pillar on the face of which toward the worksupport are provided transverse graduations spaced longitudinally ofsaid gauge member, said graduations indicating directly the differentlevels for supporting a tool bit for lapping different angles on thetool bit tip, whereby said work support with a tool bit resting thereonwith the tip disposed adjacent said gauge member is adapted to beadjusted to a predetermined position for a predetermined angle oflapping by adjusting it with the tool bit movable in close proximityrelative to the gauge member.

4. A lapping machine comprising, in combination, a suitably rotatablysupported wheel of appreciable radius having a rim with a wide flatsmooth unyielding periphery, means for driving said wheel at a highspeed, means pro viding an abrasive covering of uniform thickness on thecontour of the rim of said wheel suitable for lapping a micro-iinish onthe tip of a carbide tipped tool, means for adjustably supporting a toolbit to be lapped on the tip so that the bit is adjustable to any one ofa series of lappin positions parallel to one another and closer to orfarther away from a certain radius of the wheel, so that the greater thedistance from the said radius the greater the angle of lappingobtainable by reason of the lapping being done on the contour of thewheel, and an elongated gauge member disposed adjacent said adjustabletool bit supporting means parallel to the direction of its adjustabilityand having on the face toward said means transverse graduations spacedlongitudinally of said gauge member, said graduations indicatingdirectly the diiferent levels for supporting a tool bit for lappingdifierent angles on the tool bit tip, whereby said tool supporting meanswith a tool bit resting thereon with the tip disposed adjacent saidgauge member is adapted to be adjusted to a predetermined position for apredetermined angle of lapping by adjusting it with the tool bit movablein close proximity relative to the gauge member.

5. A lapping machine comprising, in combination, a suitably rotatablysupported wheel of appreciable radius having a rim with a wide flatsmooth unyielding periphery, means for driving said wheel at a highspeed, means providing an abrasive covering of uniform thickness on thecontour of the rim of said wheel suitable for lapping a micro-finish onthe tip of a carbide tipped tool, means for adjustably supporting a toolbit to be lapped on the tip so that the bit is adjustable to any one ofa series of lapping positions parallel to one another and closer to orfarther away from a certain radius of the wheel, so that the greater'thedistance from the said radius the greater the angle of lappingobtainable by reason of the lapping being done on the contour of theWheel, an elongated gauge member disposed adjacent said adjustable toolbit supporting means parallel to the direction of its adjustability andhaving on the face toward said means transverse graduations spacedlongitudinally of said gauge member, said graduations indicatingdirectly the different levels for supporting a tool bit for lappingdifferent angles on the tool bit tip, whereby said tool supporting meanswith a tool bit resting thereon with the tip disposed adjacent saidgauge member is adapted to be adjusted without reference to themicrometer readings to a predetermined position for a predeterminedangle of lapping by adjusting it with the tool bit movable in closeproximity relative to the gauge member, and a table of figuresrepresenting different micrometer measurements in which there iscorrelated with the angle of lapping desired the predeterminedmicrometer measurement relating to the distance of said tool supportingmeans from the aforesaid radius, the micrometer adjustment being thenadapted to be operated a slight amount one Way or the other until themicrometer reading thereon agrees with the table in so far as the giventool bit and the angle of lapping desired are concerned.

6. A lapping machine comprising, in combination, a suitably rotatablysupported wheel of appreciable radius having a rim with a wide flatsmooth unyielding periphery, means for driving said wheel at a highspeed, means providing an abrasive covering of uniform thickness on thecontour of the rim of said wheel suitable for lapping a micro-finish onthe tip of a carbide tipped tool, means for adjustably supporting a toolbit to be lapped on the tip so that the bit is adjustable to any one ofa series of lapping positions parallel to one another and closer to orfarther away from a certain radius of the wheel, so that the greater thedistance from the said radius the greater the angle of lappingobtainable by reason of the lapping being done on the contour of thewheel, said tool bit supporting means including a slide on which thework is carried adjustable in a direction at right angles to the otherdirection of adjustment described, namely, parallel to the said radiusof said wheel toward and away from the periphery thereof, and anelongated gauge member disposed adjacent said adjustable tool bitsupporting means parallel to the direction of its adjustability andhaving on the face toward said means transverse graduations spacedlongitudinally of said gauge member, said graduations indicatingdirectly the difierent levels for supporting a tool bit for lappingdifierent angles on the tool bit tip, whereby said tool supporting meanswith a tool bit resting thereon with the tip disposed adjacent saidgauge member is adapted to be adjusted to a predetermined position for apredetermined angle of lapping by adjusting it with the tool bit movablein close proximity'relative to the gauge member. I

7. In alapping machine comprising a suitably rotatably supported wheelof appreciable radius having a rim with a Wide flat smooth unyieldingperiphery, means providing an abrasive covering for said wheel suitablefor lapping a micro finish on the tip of a carbide tipped tool, meansfor driving said wheel, a work support having a surface in a planeparallel to a certain radius of said wheel on which a tool bit the tipof which is to be lapped is adapted to be supported for lapping contactwith said abrasive, a pillar on top of which said support is carried foradjustment in a guide in a direction at right angles to said radius, andmeans for adjusting said pillar in said guide, the improvement whichconsists in the provision of an arm mounted on said machine for pivotalmovement about an axis parallel to said pillar and supported accuratelyin a given plane parallel to said work support, said arm carrying anelongated gauge member disposed parallel to said pillar and having onone face thereof transverse graduations spaced longitudinally of saidmember, said graduations indicating directly the different levels forsupporting a tool bit for lapping different angles on the tool bit tip,whereby said work support with a tool bit resting thereon with the tipdisposed adjacent said gauge member is adapted to be adjusted to apredetermined elevation for a predetermined angle of lapping byadjusting said support with the tool bit movable in close proximitylengthwise relative to the gauge member.

References Cited in the file of this patent UNITED STATES PATENTS 85,537Sawyer Jan. 5, 1869 278,578 McLaughlin May 29, 1883 287,144 Madden Oct.23, 1883 462,185 Wilson et al Oct. 27, 1891 504,306 Norton Aug. 29, 18931,288,908 Johnson -Dec. 24, 1918 1,528,685 Murphy Mar. 31, 19251,841,411 Kux Jan. 19, 1932 1,981,174 Hi1le Nov. 20, 1934 2,220,268Olsen Nov.'5, 1940 2,367,107 Emmons Jan. 9, 1945 2,449,519 Sutton Sept.14, 1948 2,573,220 Riedsel et a1 Oct. 30, 1951 2,578,662 Bader Dec. 18,1951 2,597,256 Murray May 20, 1952 2,632,981 Kniep Mar. 31, 19532,663,978 Lindmark Dec. 29, 1953 FOREIGN PATENTS 67,799 7 Austria Aug.1, 1914 Switzerland Aug. 15, 1947

